The present disclosure relates generally to regional oximetry and, more particularly, to ensemble averaging of pulses in a detected waveform from a regional oximeter.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the field of medicine, medical practitioners often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of devices have been developed for monitoring physiological characteristics. Such devices provide doctors and other healthcare personnel with the information they need to provide healthcare for their patients. As a result, such monitoring devices have become an indispensable part of modern medicine. One technique for monitoring certain physiological characteristics of a patient is commonly referred to as regional oximetry, and the devices built based upon regional oximetry techniques are commonly referred to as regional oximeters.
A regional oximeter is typically used to measure various physiological characteristics, such as the blood oxygen saturation within the venous, arterial, and capillary systems within a region of a patient. Measurement of these characteristics has been accomplished by use of a non-invasive sensor that passes light through a portion of a patient's blood perfused tissue and photo-electrically senses the absorption and scattering of light in such tissue. For example, a regional oximetry sensor may include one or more emitters that emit one or more wavelengths of light and two or more detectors that photo-electrically sense the absorption and/or scattering of the light after passage through a region of the patient's tissue. During operation, a regional oximeter typically compares the relative intensities of light received at the two or more detectors to determine a regional oxygen saturation (rSO2) value that corresponds to the blood oxygen saturation within the venous, arterial, and capillary systems of the region of the patient's tissue.
Because the regional oximetry sensor detects light that has passed through the venous, arterial, and capillary systems of the region of the patient's tissue, the signal from the regional oximetry sensor (e.g., a photo-plethysmographic (PPG) signal) may include arterial pulses and venous pulses. Arterial pulses are caused by an increased volume of arterial blood ejected from the heart and may be used to determine arterial oxygen saturation. Venous pulses are caused by the return flow of venous blood to the heart and may be used to determine venous oxygen saturation. However, it may be difficult to identify the arterial and venous pulses in the PPG signal due to the placement of the regional oximetry sensor on the body (e.g., a location with a weak arterial pulse, such as the forehead) and the emitter-detector spacing of the regional oximetry sensor. Consequently, it may be difficult to separately determine arterial oxygen saturation and venous oxygen saturation using a regional oximetry sensor.